High Density, low friction plastic

High Density, low friction plastic

High Density, low friction plastic

I am looking for a plastic material that I can make a shim and cylinder out of- it needs to be strong enough to support screw threads through its sidewalls, but have low enough friction to be able to effectively slide up and down. Low wear is also a necessity. Does anyone have any material ideas for plastic on plastic sliding? The pieces are for a film thickness guage that uses the Eddy current, so no metal can be near the tip. Thanks in advance.